We used microsatellite loci to investigate the parentage of the apple cultivar `Honeycrisp', a patented University of Minnesota introduction. In an attempt to find the correct parents, we also examined other apple varieties associated with the University of Minnesota apple breeding program. Based on written records from the 1960s, the presumed parents of `Honeycrisp' were `Honeygold' and `Macoun'. We were able to exclude both of these as parents, but found that `Keepsake' was consistent as one of the parents. A second potential parent could not be discovered. `Haralson', another commercially important cultivar from the University of Minnesota, is likely from a cross between `Malinda' and `Wealthy'.
Paul R. Cabe, Andrew Baumgarten, Kyle Onan, James J. Luby, and David S. Bedford
Jong Woo Choi, Chengyan Yue, James Luby, Shuoli Zhao, Karina Gallardo, Vicki McCracken, and Jim McFerson
We conducted choice experiments with both strawberry producers and consumers. Consumer and producer willingness to pay (WTP) for the fruit attributes were estimated using mixed logit models. Through simulation using the mixed logit model results, we derived the market equilibrium prices, supply and demand curve, as well as quantities demanded and supplied for every fruit attribute. We found the highest equilibrium price was for strawberry internal color followed by flavor. Strawberry breeders can use the information when setting breeding targets, allocating resources appropriately during their breeding process and focusing on the improvement of attributes that produce the highest social surplus and total revenue.
Chengyan Yue, R. Karina Gallardo, Vicki A. McCracken, James Luby, James R. McFerson, Lan Liu, and Amy Iezzoni
Rosaceous crops (e.g., almond, apple, apricot, caneberry, cherry, pear, peach, plum, rose, and strawberry) contribute to human health and well-being and collectively constitute the economic backbone of numerous North American rural communities. We conducted a survey of U.S. and Canadian rosaceous fruit crop breeders to assess priority setting in their programs, sources of information for setting priorities, and challenges in making technical and management decisions. Input from producers and consumers was most important in establishing breeding program targets, although respondents’ direct interaction with consumers was not frequent. Breeding targets and management decisions were mostly associated with the breeder’s type of organization, scope and range of crops, and intended use of the crop (fresh, processed, or both).
Ruchen Zhou, Chengyan Yue, Shuoli Zhao, R. Karina Gallardo, Vicki McCracken, James J. Luby, and James R. McFerson
Consumer preferences for attributes of fresh peach fruit in the United States are largely unknown on a national basis. We used a choice experiment to explore market segmentation based on consumer heterogeneous preference for fruit attributes including external color, blemish, firmness, sweetness, flavor, and price. We collected the data using an online survey with 800 U.S. consumers. Using a latent class logit model, we identified three segments of consumers differing by different sets of preferred quality attributes: experience attribute-oriented consumers, who valued fruit quality (48.8% of the sample); search attribute-oriented consumers, who valued fruit appearance (33.7% of the sample); and balanced consumers, who considered search attributes and experience attributes but who valued each in a balanced way (17.5% of the sample). Each group demonstrated differentiated demographics and purchasing habits. The results have important marketing implications for peach breeders and suppliers.
Cindy Tong, Darryl Krueger, Zata Vickers, David Bedford, James Luby, Ahmed El-Shiekh, Kenneth Shackel, and Hamid Ahmadi
Many studies of apple (Malus ×domestica Borkh.) softening have been done using cultivars that eventually become mealy. We wanted to determine whether observations in these studies would be seen in a cultivar that maintains its crispness. In this paper, we compared the texture, ultrastructure, and some physiological parameters of Honeycrisp, an apple cultivar introduced in 1991 by the Minnesota Agricultural Experiment Station, with its parents and Delicious. Sensory evaluations and instrumental texture measurements showed that `Honeycrisp' maintained a crisp texture from harvest through 6 months of cold storage, whereas its parents, `Macoun' and `Honeygold', softened over the same time period. Turgor potential, cell wall composition, and ultrastructural comparisons of the fruit were made. Cell turgor potentials of `Honeycrisp' and `Delicious' were similar and greater than those of `Macoun' and `Honeygold', and clearly correlated with firmness. There were no differences in cell wall neutral sugar composition, except for arabinose, which was not highly correlated with crispness. `Honeycrisp' fruit maintained cell wall integrity after 6 months of storage, while cell walls of `Macoun' and `Honeygold' deteriorated. These data show that it is important to compare more than one cultivar when studying crispness. Honeycrisp is a cultivar that maintains its crispness through long storage without controlled atmosphere conditions. After 6 months of storage, this crispness can be attributed to a maintenance of high turgor potential and cell wall integrity.
James J. Luby, Emily E. Hoover, David S. Bedford, Shirley T. Munson, Wesley H. Gray, David K. Wildung, and Cecil Stushnoff
Seth D. Wannemuehler, James J. Luby, Chengyan Yue, David S. Bedford, R. Karina Gallardo, and Vicki A. McCracken
Incorporating DNA-informed breeding techniques can improve selection efficiency for desired traits as compared with conventional breeding methods that do not use DNA-informed techniques. Incorporation of DNA technologies requires additional costs associated with reagents, equipment, and labor. To elucidate the cost-effectiveness of DNA-informed breeding in perennial crops with multiple years per generation, we conducted a cost–benefit analysis examining incorporation of marker-assisted selection (MAS), a type of DNA-informed breeding, applied to an apple breeding program. Annual operational costs for a midwest apple breeding program were used to develop a simulation with inputs including itemized costs and per unit costs for procedures at each breeding program stage. Simulations compared costs of MAS breeding techniques to conventional breeding methods to identify the break-even point (BEP) where cost-savings associated with MAS equals the accrued additional costs. Additional sensitivity analyses were conducted to examine changes in laboratory costs, seedling maintenance costs, and seedling evaluation costs. We found the BEP for this program occurs when MAS results in a removal rate of 13.18%, and changes to other costs (i.e., maintenance costs) result in a smaller percent decrease to the overall program budget. Our findings are useful to perennial crop breeding programs in which managers are considering incorporating DNA-informed breeding techniques.
Stan C. Hokanson, James R. McFerson, Philip L. Forsline, Warren F. Lamboy, James J. Luby, Aimak D. Djangaliev, and Herb S. Aldwinckle
Cindy B.S. Tong, David S. Bedford, James J. Luby, Faye M. Propsom, Randolph M. Beaudry, James P. Mattheis, Christopher B. Watkins, and Sarah A. Weis
The effects of growing and storage locations and storage temperature on soft scald incidence of `Honeycrisp' apples were examined. In 1999 and 2000, fruits were produced at five different locations, harvested at two different times, and stored at two or five different storage locations. In 1999, fruits were stored at 0 or 2 °C. Soft scald was only observed in fruits from one growing location and primarily at 0 °C. More soft scald was observed from the second harvest than from the first. Scalded fruits were preclimacteric as determined by ethylene production rate, whereas fruits from the other locations were postclimacteric. In 2000, fruits from four of the growing locations developed soft scald, and soft scald incidence was not related to ethylene production rate. Scalded fruits had higher concentrations of phosphorus, boron, and magnesium, and lower concentrations of manganese than unaffected fruit. Development of soft scald was not related to fruit ethylene production rates, was dependent on growing location, increased with later harvest, and may be related to fruit elemental content.
Cari A. Schmitz, Matthew D. Clark, James J. Luby, James M. Bradeen, Yingzhu Guan, Katherine Evans, Benjamin Orcheski, Susan Brown, Sujeet Verma, and Cameron Peace
Establishing marker-locus-trait associations to enable marker-assisted breeding depends on having an extensive, reliable database for phenotypic traits of interest in relevant germplasm. A reference germplasm set of 467 apple (Malus ×domestica Borkh.) cultivars, selections, and seedlings (referred to as individuals) was identified as part of the USDA-Specialty Crop Research Initiative (SCRI) project, RosBREED. The germplasm set provides efficient allelic representation of current parents in RosBREED demonstration apple breeding programs at Cornell University, Washington State University, and the University of Minnesota. Phenotyping at the three locations was conducted according to standardized protocols, focusing on fruit traits evaluated at harvest and after 10 and 20 weeks of refrigerated storage. Phenotypic data were collected for the sensory texture traits of firmness, crispness, and juiciness as well as for instrumental texture measures. In 2010 and 2011, fruit from 216 and 330 individuals, respectively, were harvested and a total of 369 individuals were evaluated over the two years. Correlations between sensory and instrumental texture measures were high in some instances. Moderate year-to-year repeatability of trait values was observed. Because each location had a largely unique set of individuals, as well as differing environmental conditions, means, ranges, and phenotypic variances differed greatly among locations for some traits. Loss of firmness and crispness during storage was more readily detected instrumentally than by the sensory evaluation.